The present invention relates to a stylus for key duplicating machine, and more particularly to a stylus for key duplicating machine with replaceable segmented stylus which primarily comprises a cylindrical body; a spring-loaded tracer having a slide spindle movably engaged in one end of the cylindrical body, and a replaceable segmented stylus releasably secured on the front end of the slide spindle for replacement of the worn replaceable segmented stylus by new one easily; and a regulating grip angularly movably engaged in the other end of the cylindrical body.
There are two kinds of styluses in the conventional stylus for key duplicating machine for duplicating a key for the cylinder lock which comprises a wave-shaped pattern of the teeth; a stationary wedge-shaped stylus; and a spring-loaded semi-cylindrical stylus having a hypotenuse end. Although both the stationary wedge-shaped stylus and the spring-loaded semi-cylindrical stylus are integrally made by hard material e.g. a medium carbon steel which should be subjected to heat treatment, in order to enhance its hardness during manufacturing, the tip of the stylus which will tightly touch and trace the wave-shaped pattern of the teeth formed on the original key, and be worn out when the same traces the wave-shaped pattern of the teeth frequently during key duplicating. Once the tip of the stylus is seriously worn out, the tracing of the wave-shaped pattern of the teeth formed on the originally key would be inaccurate, and result in an inaccurate key cutting, i.e. inaccurate depths of the formed key teeth. Generally speaking, after the stylus made by the material of the medium carbon steel has been used about 20,000-30,000 times, the tip of the stylus would be seriously worn out while the remainder undamaged parts of the stylus remain useful, and the whole stylus would be thrown away.
The present invention aims at eliminating the above disadvantages and provides a stylus for key duplicating machine with replaceable segmented stylus, wherein a replaceable segmented stylus is provided for use as a tracer, and for replacement of the worn replaceable segmented stylus by new one easily, in order to enhance the accuracy of the key duplicating, and to save the cost of the stylus.
In a preferred aspect of the present invention, the stylus for key duplicating machine with replaceable segmented stylus comprises a cylindrical body; a spring-loaded tracer having a slide spindle movably engaged in one end of the cylindrical body, and a replaceable segmented stylus releasably secured on the front end of the slide spindle for replacement of the worn replaceable segmented stylus by new one easily; and a regulating grip angularly movably engaged in the other end of the cylindrical body.